Feature: Add support for compiling native libraries for the VESC Expr…

.gitignore

@@ -11,3 +11,4 @@ confxml.h
 *.cproject
 *.project
 *.settings
+*.vscode

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "c_libs/RVfplib"]
+	path = c_libs/RVfplib
+	url = [email protected]:pulp-platform/RVfplib.git

README.md

@@ -91,6 +91,11 @@ make clean
 make VESC_TOOL=/path/to/vesc_tool
 ```
 
+For building native libraries for VESC Express with c_libs you will need to specify the architecture:
+```sh
+make ARCH=esp32
+```
+
 ### Notes
 
 * Make sure that you build a VESC Package file (\*.vescpkg) in the main directory of your package (e.g. euc/euc.vescpkg)

c_libs/link_esp32.ld

@@ -0,0 +1,11 @@
+SECTIONS
+{
+    . = 0;
+    .program_ptr : ALIGN(4) { *(.program_ptr) } /* offset 0 */
+    .init_fun : ALIGN(4) { *(.init_fun) }
+
+    .text : ALIGN(4) { *(.text*) *(.rodata*) }
+    .data : ALIGN(4) { *(.data*) }
+    .bss : ALIGN(4) { *(.bss*) }
+    .got : ALIGN(4) { *(.got*) }
+}

c_libs/rules.mk

@@ -1,3 +1,15 @@
+# ======================================================================
+# Unified Makefile for STM32F4 (default) and ESP32-C3 (minimal)
+# ======================================================================
+
+# ------------------------- Arch selection ------------------------------
+ARCH ?= stm32
+ifeq ($(ESP_PLATFORM),true)
+  ARCH := esp32
+endif
+
+# CROSS prefix per arch (override if you like)
+ifeq ($(ARCH),stm32)
 
 CC = arm-none-eabi-gcc
 LD = arm-none-eabi-gcc
@@ -67,4 +79,159 @@ $(TARGET): $(OBJECTS)
 
 clean:
 	rm -f $(OBJECTS) $(TARGET).elf $(TARGET).list $(TARGET).lisp $(TARGET).bin
+else ifeq ($(ARCH),esp32)
+# ======================================================================
+#  ESP32-C3   Native-lib rules (PIC blob for LispBM)
+#  - RISC-V (rv32imc / ilp32, software float)
+#  - Section GC + (optional) LTO
+#  - Generates: .elf, .bin (with header), .lisp, .list, .map
+# ======================================================================
+
+# ---- toolchain (override CROSS if needed) -----------------------------
+CROSS     ?= riscv32-esp-elf-
+CC        := $(CROSS)gcc
+AR        := $(CROSS)ar
+OBJDUMP   := $(CROSS)objdump
+OBJCOPY   := $(CROSS)objcopy
+NM        := $(CROSS)nm
+READELF   := $(CROSS)readelf
+PYTHON    ?= python3
+
+# ---- project defaults (override if you like) --------------------------
+TARGET   ?= package_lib
+SOURCES  ?=
+
+# ---- paths ------------------------------------------------------------
+VESC_C_LIB_PATH ?= ../..
+LINKER_SCRIPT   ?= $(VESC_C_LIB_PATH)/link_esp32.ld
+
+# ---- RVfplib (required) -----------------------------------------------
+# Expect RVfplib sources at $(VESC_C_LIB_PATH)RVfplib/
+# Always produce and link $(VESC_C_LIB_PATH)librvfp.a
+RVFP_SRC_DIR   := $(VESC_C_LIB_PATH)/RVfplib
+RVFP_VARIANT   ?= rvfp_nd_s
+RVFP_LIB := $(RVFP_SRC_DIR)/build/lib/lib$(RVFP_VARIANT).a
+
+# ---- toggles ----------------------------------------------------------
+USE_LTO      ?= no        # Use LTO if your riscv32-esp-elf toolchain supports it
+VERBOSE_LINK ?= yes       # Emit a link map and (optionally) GC diagnostics
+
+# Exported entry symbols (kept even with GC/LTO)
+ENTRY_SYMS ?= init
+
+# ---- common flags -----------------------------------------------------
+CFLAGS_COMMON = \
+  -Os -Wall -Wextra -Wundef -std=gnu99 \
+  -ffunction-sections -fdata-sections \
+  -fPIC -fvisibility=hidden \
+  -I$(VESC_C_LIB_PATH) -DIS_VESC_LIB \
+  -DESP_PLATFORM=true \
+  -march=rv32imc_zicsr_zifencei -mabi=ilp32 \
+  -mno-save-restore \
+  -mcmodel=medany \
+  -msmall-data-limit=0 \
+  -Wdouble-promotion -Wfloat-conversion \
+  -Werror=implicit-function-declaration \
+  -Werror=incompatible-pointer-types \
+  -Werror=int-conversion \
+  -Werror=return-type
+
+ifeq ($(USE_LTO),yes)
+  CFLAGS_COMMON += -flto
+  LDFLAGS_LTO   = -flto
+else
+  LDFLAGS_LTO   =
+endif
+
+# Dependency generation
+CFLAGS_DEPS = -MMD
+
+CFLAGS += $(CFLAGS_COMMON) $(CFLAGS_DEPS)
+
+# ---- link flags -------------------------------------------------------
+LDFLAGS = \
+  -static \
+  -Wl,--gc-sections \
+  -Wl,--no-relax \
+  -Wl,--no-warn-rwx-segments \
+  -T $(LINKER_SCRIPT) \
+  -Wl,-Map=$(TARGET).map \
+  $(LDFLAGS_LTO)
+
+# Keep required entry points
+LDFLAGS += $(foreach s,$(ENTRY_SYMS),-Wl,--undefined=$(s))
+
+# Helpful traces (you can comment these out if too chatty)
+LDFLAGS += -Wl,--trace-symbol=__mulsf3 -Wl,--trace-symbol=__divsf3
+LDFLAGS += -Wl,--trace-symbol=__addsf3 -Wl,--trace-symbol=__subsf3
+LDFLAGS += -Wl,--trace-symbol=__eqsf2  -Wl,--trace-symbol=__nesf2
+
+# Diagnostics
+ifeq ($(VERBOSE_LINK),yes)
+  # Uncomment to see stripped sections:
+  # LDFLAGS += -Wl,--print-gc-sections
+endif
+
+# ---- required soft-float libs (group avoids cyclic deps) --------------
+# Always link the locally-built librvfp.a first
+LDGROUP := -Wl,--start-group $(RVFP_LIB) -Wl,--end-group
+
+# ---- derived names ----------------------------------------------------
+OBJECTS := $(SOURCES:.c=.o)
+DEPS    := $(SOURCES:.c=.d)
+ELF     := $(TARGET).elf
+BIN     := $(TARGET).bin
+LISP    := $(TARGET).lisp
+LIST    := $(TARGET).list
+MAP     := $(TARGET).map
+
+# ---- phony ------------------------------------------------------------
+.PHONY: default all clean nmcheck disasm rvfp
+
+default: $(TARGET)
+all:     default
+
+# ---- auto-build librvfp.a (no checks; assumes RVfplib exists) --------
+$(RVFP_LIB):
+	@echo ">> Building RVfplib ($(RVFP_VARIANT)) with $(CROSS)"
+	$(MAKE) -C "$(RVFP_SRC_DIR)" \
+		RISCV_PREFIX=$(CROSS) ARCH=rv32imc ABI=ilp32 \
+		CC=$(CC) AR=$(AR) NM=$(NM) OBJDUMP=$(OBJDUMP)
+
+rvfp: $(RVFP_LIB)
+
+# ---- build rules ------------------------------------------------------
+$(TARGET): $(ELF)
+	$(OBJCOPY) -O binary $< [email protected]
+	echo 'cafebabe' | xxd -r -p > [email protected]
+	cat [email protected] >> [email protected]
+	rm [email protected]
+	$(PYTHON) $(VESC_C_LIB_PATH)/conv.py -f [email protected] -n $(TARGET) > $(LISP)
+
+$(ELF): $(OBJECTS) $(RVFP_LIB)
+	$(CC) $(OBJECTS) $(CFLAGS) $(LDFLAGS) $(LDGROUP) -o $@
+	$(OBJDUMP) -D $@ > $(LIST)
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+clean:
+	rm -f $(OBJECTS) $(DEPS) $(ELF) $(BIN) $(LISP) $(LIST) $(MAP) $(ADD_TO_CLEAN)
+
+# ---- helpers ----------------------------------------------------------
+nmcheck: $(ELF)
+	@echo "# soft-float helpers present (T=defined, U=undefined):"
+	$(NM) $(ELF) | egrep '__subsf3|__addsf3|__mulsf3|__divsf3|__eqsf2|__nesf2' || true
+	@echo
+	@echo "# relocations against helpers (should usually be none):"
+	$(READELF) -r $(ELF) | egrep '__subsf3|__addsf3|__mulsf3|__divsf3|__eqsf2|__nesf2' || true
+
+disasm: $(ELF)
+	$(OBJDUMP) -drwC --disassemble=buffer_get_float16 $(ELF) | sed -n '1,200p'
+
+# Include auto-generated dependencies
+-include $(DEPS)
 
+else
+  $(error Unknown ARCH=$(ARCH); use stm32 or esp32)
+endif